Variable volume horn system



Filed Dec. 1, 1960 OSCILLATOR OSCILLATOR MULT.

INVENTOR. Duane E. Atkinson Attorneys United States Patent 3,173,136 VARIABLE VOLUME HORN SYSTEM Duane E. Atkinson, 102 Fey Drive, Burlingame, Calif. Filed Dec. 1, 1960, Ser. No. 73,052 5 Claims. (Cl. 340-384) The invention relates to horn systems and more particularly to horns for vehicles which may be used in areas having variable noise levels.

In many applications horns are utilized in vehicles as a warning device not only for normal forward driving of the vehicle, but also when backing up. In most applications, horns of predetermined volume are chosen. Such horns are ordinarily adequate. However, in many areas, for example when back-up warning horns are employed on heavy construction projects, the noise level of the environment is sufficiently high that the sound of the horn cannot be readily distinguished. If an exceedingly loud horn were utilized on the vehicles in such application, its use would be obnoxious during operation in quieter areas.

It is, therefore, an object of this invention to provide an improved horn wherein the volume of the horn is automatically variable depending upon the background noise level.

It is a more particular object of this invention to provide a horn of the above mentioned character wherein a variable output amplifier is utilized to vary the volume of the horn.

It is another object of this invention to provide an automatic controlled horn wherein a microphone is alternately used with the horn to determine background noise.

It is another object of this invention to provide an automatic volume horn wherein the horn itself is alternately used as a horn and a microphone for determining the background noise.

These and other features and objects of the invention will become more clearly apparent upon reading the following description in conjunction with the accompanying drawing in which:

FIGURE 1 is a schematic diagram of one embodiment of the invention employing a horn and a microphone alternately utilized to sound a signal and monitor the background noise; and

FIGURE 2 is a schematic diagram of another embodiment of the invention wherein a single horn is alternately used to sound an alarm and to monitor the background noise.

Referring particularly to FIGURE 1, an oscillator 11 is shown connected through a coincidence gate 13 and a variable output amplifier 15 to a speaker horn 17. An astable multivibrator 19 has one of its outputs connected as another input to the coincidence gate 13.

A pickup or transducer, for example, a microphone 21 has its output connected to a second coincidence gate 23 and a capacitor 25 to ground. The output of the coincidence gate 23 is also connected through the diode 27 as a bias input to the amplifier 15. The other output of the multivibrator 19 is applied as a second input to the coincidence gate 23.

In operation the oscillator 11 produces an output signal having the desired horn frequency. In one of the astable states of the multivibrator 19, the gate 13 is activated whereby the signal from the oscillator may be applied to the amplifier 15 for amplification. The output of the amplifier is then applied directly to the speaker 17 to produce an audible signal.

The microphone 21 continuously picks up not only the background noise but the signal produced by the speaker 17. The output of the microphone 21, being applied to the coincidence gate 23, is operable only on signal from the multivibrator 19. The multivibrator 19 permits only ice one of the gates 13 or 23 to be operated at any given time. Thus, the noise produced by the alarm or speaker 17 is not passed through the gate 23. Only the background noise is passed from the microphone 21 through the gate 23. The output of the gate 23 is rectified by the diode 27.

Capacitor 25 stores or integrates the background noise voltage rectified by diode 27 to provide an essentially steady bias voltage during the switching cycle of gates 13 and 23. This voltage is applied as a positive bias control signal to the amplifier 15. Thus, upon an increase in background noise, the amplifier 15 receives more positive bias thereby producing a higher output. It is seen that the volume from the speaker 17 is determined automatically by the background noise.

In the embodiment shown in FIGURE 2, the speaker 17 performs a function of both the speaker 17 and microphone 21 of FIGURE 1. Operation of the circuit of FIGURE 2 is identical to that of the circuit of FIGURE 1 wherein the element 17 acts as a speaker and a microphone alternately as determined by the multivibrator 19.

I claim:

1. A variable volume horn system comprising a first coincidence gate, an oscillator having its output connected as an input to said first coincidence gate, a multivibrator having one of its outputs connected as a second input to said first coincidence gate, an amplifier having an output variable in response to a control signal, the output of said first coincidence gate being applied as an input to the variable amplifier, first transducing means, the output of said amplifier being coupled to said first transducing means, second transducing means, a second coincidence gate, the output of said second transducing means being coupled to as an input to said second coincidence gate, the other output of said multivibrator being coupled as a second input to said second coincidence gate, the output of said second coincidence gate being coupled to said variable amplifier as said control signal for varying the output of the amplifier in accordance with the output of said second transducer means.

2. A variable volume horn system comprising a first coincidence gate, an oscillator having its output connected to said first coincidence gate, a multivibrator having one of its outputs connected as a second input to said first coincidence gate, an amplifier having an output variable in response to a control signal, the output of said first coincidence gate being applied as an input to the variable amplifier, first transducing means, the output of said amplifier being coupled to said first transducing means, second transducing means, a second coincidence gate, the output of said second transducing means being coupled to said second coincidence gate, the other output of said multivibrator being coupled as a second input to said second coincidence gate, a rectifier connected to rectify the output of the second coincidence gate, and integrating means serving to receive and integrate the rectified output and apply the same to said variable amplifier as said control signal for varying the output of the amplifier in accordance with the output of said second transducer means.

3. A variable volume horn comprising a first coincidence gate, an oscillator having its output connected to said first coincidence gate, a multivibrator having one of its outputs connected as another input to said first coincidence gate, a variable output amplifier, the output of said first coincidence gate being applied as an input to said variable output amplifier, transducing means, the output of said amplifier being coupled to said transducing means, a second coincidence gate, said transducing means being coupled as an input to said second coincidence gate, the other output of said multivibrator being coupled as another input to said second coincidence gate, the output Patented Mar. 9, 1965 3 of saidsecondcoincidence gate being coupled to said variable amplifier asa bias.

4. A variable volume horn comprising a first coincidence gate, an oscillator having its output connected to said coincidence gate, asmult-ivibrator having, one of its outputs connectedas another input to-said first coincidence gate, a variable output amplifier, the output of said first coincidence gate being applied asan input to said variable output amplifier, transducing means, theroutput of said amplifier being coupled to ,said: transducing means, asecond coincidence gate, said'transducingjrneansbeing coupled to said second:coincidence gate, the other output of said multivibrator being coupled as another input to said second coincidence .gate, a rectifier connected to rectify the output ofathe second. coincidence gate, and integrating means serving to receive'and integrate the rectified output and apply. the same to, said variable output amplifier as a bias.

-5. Asystem otthe character described comprising signal generating means for producingan electrical alarm signal, transducerrmeans for transducing said electrical alarm signal;-intoau audiblesignal and for transducing environmental audible signals intoisecondelect-rical signals, amplifying means having an input, an. output and a bias input, first gating means coupling the output of said signal generating means to the input of said amplitying means, the output of said amplifying means being coupled to said transducer means, second gating means coupling said transducer means to the bias input of said amplifying means, and means for alternatively operating said first andsecond gating-means whereby in a-first condition-of operation said electrical alarm signal is passed through saidamplifying means-to said transducer means and in a second condition of operationa second electrical signal is applied to said bias input for varying the output of saidzamplifying means in accordance with the environmental audible Signals received by said transducer means.

References Cited in the 'fileofthis patent UNITED STATES PATENTS 1,661,058 ITheremin Feb. 28,1928

2,165,509 Ring et al. July 11, 1939 2,910,689 Grace Oct. 27, .1959

2,963,693 Capalozza Dec. 6, 19.60

3,049,699 Larricket al Aug. 14, 1962 FOREIGN PATENTS 1,091,421 France Oct. 27, 1954 

1. A VARIABLE VOLUME HORN SYSTEM COMPRISING A FIRST COINCIDENCE GATE, AN OSCILLATOR HAVING ITS OUTPUT CONNECTED AS AN INPUT TO SAID FIRST COINCIDENCE GATE, A MULTIVIBRATOR HAVING ONE OF ITS OUTPUT CONNECTED AS A SECOND INPUT TO SAID FIRST COINCIDENCE GATE, AN AMPLIFIER HAVING AN OUTPUT VARIABLE IN RESPONSE TO A CONTROL SIGNAL, THE OUTPUT OF SAID FIRST COINCIDENCE GATE BEING APPLIED AS AN INPUT TO THE VARIABLE AMPLIFIER, FIRST TRANSDUCING MEANS, THE OUTPUT OF SAID AMPLIFIER BEING COUPLED TO SAID FIRST TRANSDUCING MEANS, SECOND TRANSDUCING MEANS, A SECOND COINCIDENCE GATE, THE OUTPUT OF SAID SECOND TRANSDUCING MEANS BEING COUPLED TO AS AN INPUT TO SAID SECOND COINCIDENCE GATE, THE OTHER OUTPUT OF SAID MULTIVIBRATOR BEING COUPLED AS A SECOND INPUT TO SAID SECOND COINCIDENCE GATE, THE OUTPUT OF SAID SECOND COINCIDENCE GATE BEING COUPLED TO SAID VARIABLE AMPLIFIER AS SAID CONTROL SIGNAL FOR VARYING THE OUTPUT OF THE AMPLIFIER IN ACCORDANCE WITH THE OUTPUT OF SAID SECOND TRANSDUCER MEANS. 